1. Field of the Invention
This invention relates to a scheme for delivering confirmation packets to mobile hosts affiliated with an Internet protocol (IP) network.
2. Discussion of the Known Art
In networks that support mobility, the precise location of a mobile host must be known before data addressed to the host can be delivered. There is a tradeoff between how closely the network tracts the host's current location, and the processing time required to locate the host when its current position is not precisely known beforehand.
Tracking the location of the mobile host involves procedures in which the host informs the network of its location at times triggered by movement, timer expiration, and the like. Specific protocols for tracking an IP mobile host are given in Request for Comment (RFC) 2002 of the Internet Engineering Task Force (IETF), all relevant portions of which are incorporated herein by reference.
Efforts are now underway to integrate both indoor (LAN) and outdoor (WAN) wireless access technologies over a common IP based access network. Such would allow more flexibility in deploying equipment which may greatly reduce network operation costs. In addition, an IP based access network should be able to support both voice and data services on a common infrastructure, resulting in seamless support of services across both wired and wireless networks. Such IP based networks are expected to be a basis for future third and fourth generation wireless networks.
It is known that the location of a mobile host can be determined using procedures such as paging that trigger a response from the mobile host. Paging typically involves transmitting a request for a given host to a number of potential locations of the host. This set of locations is defined as a paging area, and the area corresponds to an overall scope of coverage of a set of neighboring base stations.
A paging service is available in wireless wide-area networks (WAN) such as the General Packet Radio Service (GPRS), and CDMA data. Wireless local area network (LAN) protocols such as IEEE 802.11 also have the notion of a power-save state. That is, paging is deployed in these networks as a means for waking a mobile host from a standby or power-save state to an active state, at a single base station of the network. The paging architecture and protocols in each of the networks are defined independently and do not inter-operate. Because of this, seamless movement of the mobile host between local-area and wide-area networks, or between wide-area networks of different types, is precluded. The mobility protocol for IP networks set out in RFC 2002 does not disclose or suggest a paging feature with a view toward power conservation at an IP mobile host.